BCAT1 is a NOTCH1 target and sustains the oncogenic function of NOTCH1.

High levels of branched-chain amino acid (BCAA) transaminase 1 (BCAT1) have been associated with tumor aggressiveness and drug resistance in several cancer types. Nevertheless, the mechanistic role of BCAT1 in T-cell acute lymphoblastic leukemia (T-ALL) remains uncertain. We provide evidence that Bcat1 was over-expressed following NOTCH1-induced transformation of leukemic progenitors and that NOTCH1 directly controlled BCAT1 expression by binding to a BCAT1 promoter. Further, using a NOTCH1 gain-of-function retroviral model of T-ALL, mouse cells genetically deficient for Bcat1 showed defects in developing leukemia. In murine T-ALL cells, Bcat1 depletion or inhibition redirected leucine metabolism towards production of 3-hydroxy butyrate (3-HB), an endogenous histone deacetylase inhibitor. Consistently, BCAT1 depleted cells showed altered protein acetylation levels which correlated with a pronounced sensitivity to DNA damaging agents. In human NOTCH1-dependent leukemias, high expression levels of BCAT1 may predispose to worse prognosis. Therapeutically, BCAT1 inhibition specifically synergized with etoposide to eliminate tumors in patient-derived xenograft models suggesting that BCAT1 inhibitors may have a part to play in salvage protocols for refractory T-ALL.

Integrating Protein Interaction Surface Prediction with a Fragment-Based Drug Design: Automatic Design of New Leads with Fragments on Energy Surfaces.

Protein-protein interactions (PPIs) have emerged in the past years as significant pharmacological targets in the development of new therapeutics due to their key roles in determining pathological pathways. Herein, we present fragments on energy surfaces, a simple and general design strategy that integrates the analysis of the dynamic and energetic signatures of proteins to unveil the substructures involved in PPIs, with docking, selection, and combination of drug-like fragments to generate new PPI inhibitor candidates. Specifically, structural representatives of the target protein are used as inputs for the blind physics-based prediction of potential protein interaction surfaces using the matrix of low coupling energy decomposition method. The predicted interaction surfaces are subdivided into overlapping windows that are used as templates to direct the docking and combination of fragments representative of moieties typically found in active drugs. This protocol is then applied and validated using structurally diverse, important PPI targets as test systems. We demonstrate that our approach facilitates the exploration of the molecular diversity space of potential ligands, with no requirement of prior information on the location and properties of interaction surfaces or on the structures of potential lead compounds. Importantly, the hit molecules that emerge from our ab initio design share high chemical similarity with experimentally tested active PPI inhibitors. We propose that the protocol we describe here represents a valuable means of generating initial leads against difficult targets for further development and refinement.

Brentuximab vedotin in the treatment of paediatric patients with relapsed or refractory Hodgkin's lymphoma: Results of a real-life study.

BACKGROUND: Brentuximab vedotin (BV) is an antibody drug-conjugated anti-CD30 approved for the treatment of adult classical Hodgkin's lymphoma (HL), whereas it is considered as off-label indication in paediatrics. The aim of the study was to evaluate the safety and efficacy of BV to treat patients aged less than 18 years with refractory/relapsed HL. MATERIALS AND METHODS: In this multicentre, retrospective study, 68 paediatric patients who received at least one dose of BV between November 2011 and August 2020 were enrolled. A median of nine doses of BV were administered as monotherapy (n = 31) or combined with other therapies (n = 37). BV was administrated alone as consolidation therapy after stem cell transplantation (SCT) in 12 patients, before SCT in 18 patients, whereas in 15 patients it was used before and after SCT as consolidation therapy. Median follow-up was 2.8 years (range: 0.6-8.9 years). RESULTS: The best response was observed in the 86% of patients; the overall response rate was 66%. The 3-year progression-free survival was 58%, whereas the overall survival was 75%. No statistically significant differences between patients treated with BV monotherapy or combination were highlighted. In multivariate analysis, patients with non-nodular sclerosis HL and not transplanted had an increased risk of failure. Overall, 46% of patients had grade 3-4 adverse events that led to BV discontinuation in five of them. CONCLUSION: In conclusion, our study confirms that BV was a safe and effective drug, able to induce complete remission, either as monotherapy or in association with standard therapy.

Quantitative Plasma Proteomics to Identify Candidate Biomarkers of Relapse in Pediatric/Adolescent Hodgkin Lymphoma.

Classical pediatric Hodgkin Lymphoma (HL) is a rare malignancy. Therapeutic regimens for its management may be optimized by establishing treatment response early on. The aim of this study was to identify plasma protein biomarkers enabling the prediction of relapse in pediatric/adolescent HL patients treated under the pediatric EuroNet-PHL-C2 trial. We used untargeted liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based proteomics at the time of diagnosis­before any therapy­as semiquantitative method to profile plasma proteins specifically associated with relapse in 42 children with nodular sclerosing HL. In both the exploratory and the validation cohorts, six proteins (apolipoprotein E, C4b-binding protein α chain, clusterin, fibrinogen γ chain, prothrombin, and vitronectin) were more abundant in the plasma of patients whose HL relapsed (|fold change| ≥ 1.2, p < 0.05, Student's t-test). Predicting protein function with the Gene Ontology classification model, the proteins were included in four biological processes (p < 0.01). Using immunoblotting and Luminex assays, we validated two of these candidate biomarkers­C4b-binding protein α chain and clusterin­linked to innate immune response function (GO:0045087). This study identified C4b-binding protein α chain and clusterin as candidate early plasma biomarkers of HL relapse, and important for the purpose of shedding light on the molecular scenario associated with immune response in patients treated under the EuroNet-PHL-C2 trial.

Primary breast lymphoma of childhood: a case report and review of literature.

BACKGROUND: Primary breast lymphoma (PBL) is an extremely rare neoplasm in children; by definition, it manifests in the breast without evidence of lymphoma elsewhere, except ipsilateral axillary nodes. CASE PRESENTATION: We report a case of a 15-year-old girl diagnosed with diffuse large B-cell lymphoma (DLBCL) of the right breast: the patient received chemotherapy and rituximab, achieving complete remission. A literature review revealed other 11 cases of pediatric PBL; it mainly affects female adolescents and can involve right and left breast equally. Different histologic subtypes have been described, arising from both B-cell and T-cell. Therapeutic approaches were very different, from chemotherapy to local treatment with surgery and/or radiotherapy. CONCLUSIONS: Our case is the first in which rituximab was administered, suggesting to be a promising therapy in B-cell PBL, as already demonstrated in pediatric B-cell lymphoma from other sites. Further investigations are needed to identify prognostic factors and establish the most effective treatment.

Histology of pediatric classic Hodgkin lymphoma: From diagnosis to prognostic stratification.

AIMS: Classic Hodgkin lymphoma (cHL) is a common malignancy of the pediatric age. Although clinical-radiological features are routinely used for disease risk stratification, the role of tumor histology has yet to be defined. This study aimed to characterize the clinical-pathological features of a large cohort of pediatric cHL specifically investigating the relevance of tumor histology for the prognostic stratification of patients. METHODS AND RESULTS: The study considered 96 clinically annotated cases of pediatric cHL treated according to the AIEOP-LH2004 protocol. The following histological parameters were considered: (i) cHL variant; (ii) grade of nodular sclerosis (NS); (iii) staining for Bcl2 and p53, and expression of B-cell (BCA) and T-cell antigens (TCA) by Hodgkin/Reed-Sternberg cells. The study population consisted of 51 males and 45 females (median age: 13.6 years) with five-year overall and progression-free survival of 94% and 81%, respectively. Most cases featured NS morphology (96%) with a prevalence of NS1 over NS2 grades. Two NS2 variants were recognized (sarcomatous/syncytial and fibrohistiocytic). A consistent subset of cases disclosed positivity for BCA (34%), TCA (26%), p53 (13%), and Bcl2 (19%). Clinical-pathological correlations showed a more aggressive clinical course for NS2 over NS1 cases. The NS2 fibrohistiocytic variant was associated with the worst outcome. No other histological features correlated with prognosis. CONCLUSIONS: Pediatric cHL is a clinically and histologically heterogeneous neoplasm. The majority of cases disclose NS morphology and aberrant phenotypes are frequently encountered. In the pediatric population, NS grading and NS2 subtyping bear significant prognostic impact.

Successful Treatment of an EBV-positive Diffuse Large B-Cell Lymphoma in a Patient With Trisomy 21.

Diffuse large B-cell Lymphoma (DLBCL) secondary to a chronic severe Epstein-Barr virus (EBV) infection has not been previously described in a patient with trisomy 21. Here we report the case of a 14-year-old girl with trisomy 21 with impaired control of EBV and DLBCL. She was cured with dose-adapted chemotherapy and hematopoietic stem cell transplantation without severe treatment-related toxicity. We describe the first case of EBV-positive DLBCL in a patient with trisomy 21 and we propose a treatment modality for this rare entity.

MiR&moRe2: A Bioinformatics Tool to Characterize microRNAs and microRNA-Offset RNAs from Small RNA-Seq Data.

MicroRNA-offset RNAs (moRNAs) are microRNA-like small RNAs generated by microRNA precursors. To date, little is known about moRNAs and bioinformatics tools to inspect their expression are still missing. We developed miR&moRe2, the first bioinformatics method to consistently characterize microRNAs, moRNAs, and their isoforms from small RNA sequencing data. To illustrate miR&moRe2 discovery power, we applied it to several published datasets. MoRNAs identified by miR&moRe2 were in agreement with previous research findings. Moreover, we observed that moRNAs and new microRNAs predicted by miR&moRe2 were downregulated upon the silencing of the microRNA-biogenesis pathway. Further, in a sizeable dataset of human blood cell populations, tens of novel miRNAs and moRNAs were discovered, some of them with significantly varied expression levels among the cell types. Results demonstrate that miR&moRe2 is a valid tool for a comprehensive study of small RNAs generated from microRNA precursors and could help to investigate their biogenesis and function.

Proteomic Profiles and Biological Processes of Relapsed vs. Non-Relapsed Pediatric Hodgkin Lymphoma.

The identification of circulating proteins associated with relapse in pediatric Hodgkin lymphoma (HL) may help develop predictive biomarkers. We previously identified a set of predictive biomarkers by difference gel electrophoresis. Here we used label-free quantitative liquid chromatography-mass spectrometry (LC-MS/MS) on plasma collected at diagnosis from 12 children (age 12-16 years) with nodular sclerosis HL, including six in whom the disease relapsed within 5 years of treatment in the LH2004 trial. Plasma proteins were pooled in groups of three, separately for non-relapsing and relapsing HL, and differentially abundant proteins between the two disease states were identified by LC-MS/MS in an explorative and validation design. Proteins with a fold change in abundance >1.2 or ≤0.8 were considered "differentially abundant". LC-MS/MS identified 60 and 32 proteins that were more abundant in non-relapsing and relapsing HL plasma, respectively, in the explorative phase; these numbers were 39 and 34 in the validation phase. In both analyses, 11 proteins were more abundant in non-relapsing HL (e.g., angiotensinogen, serum paraoxonase/arylesterase 1, transthyretin), including two previously identified by difference gel electrophoresis (antithrombin III and α-1-antitrypsin); seven proteins were more abundant in relapsing HL (e.g., fibronectin and thrombospondin-1), including two previously identified proteins (fibrinogen ß and γ chains). The differentially abundant proteins participated in numerous biological processes, which were manually grouped into 10 biological classes and 11 biological regulatory subclasses. The biological class Lipid metabolism, and its regulatory subclass, included angiotensinogen and serum paraoxonase/arylesterase 1 (more abundant in non-relapsing HL). The biological classes Immune system and Cell and extracellular matrix architecture included fibronectin and thrombospondin-1 (more abundant in relapsing HL). These findings deepen our understanding of the molecular scenario underlying responses to therapy and provide new evidence about these proteins as possible biomarkers of relapse in pediatric HL.

MicroRNA 28 controls cell proliferation and is down-regulated in B-cell lymphomas.

Burkitt lymphoma (BL) is a highly aggressive B-cell non-Hodgkin lymphoma (B-NHL), which originates from germinal center (GC) B cells and harbors translocations deregulating v-myc avian myelocytomatosis viral oncogene homolog (MYC). A comparative analysis of microRNAs expressed in normal and malignant GC B cells identified microRNA 28 (miR-28) as significantly down-regulated in BL, as well as in other GC-derived B-NHL. We show that reexpression of miR-28 impairs cell proliferation and clonogenic properties of BL cells by modulating several targets including MAD2 mitotic arrest deficient-like 1, MAD2L1, a component of the spindle checkpoint whose down-regulation is essential in mediating miR-28-induced proliferation arrest, and BCL2-associated athanogene, BAG1, an activator of the ERK pathway. We identify the oncogene MYC as a negative regulator of miR-28 expression, suggesting that its deregulation by chromosomal translocation in BL leads to miR-28 suppression. In addition, we show that miR-28 can inhibit MYC-induced transformation by directly targeting genes up-regulated by MYC. Overall, our data suggest that miR-28 acts as a tumor suppressor in BL and that its repression by MYC contributes to B-cell lymphomagenesis.

Paediatric non-Hodgkin lymphoma - perspectives in translational biology.

Exciting advances have been achieved for infants, children and adolescents diagnosed with, and treated for, non-Hodgkin lymphoma (NHL). In spite of these successes, new frontiers are being paved to improve the prognosis for those who relapse or have resistant disease. This review summarizes some of the novel approaches and ideas in NHL monitoring, diagnosis and treatment as discussed at the 5th International Symposium on Childhood, Adolescent and Young Adult Non-Hodgkin Lymphoma on October 22nd-24th 2015 in Varese, Italy.

Detection of prognostic factors in children and adolescents with Burkitt and Diffuse Large B-Cell Lymphoma treated with the AIEOP LNH-97 protocol.

Burkitt lymphoma (BL) and Diffuse Large B-Cell Lymphoma (DLBCL) account for most cases of non-Hodgkin lymphoma (NHL) in childhood. We report the clinical characteristics, outcome and prognostic factors in children with BL or DLBCL treated according to the Associazione Italiana Ematologia Oncologia Pediatrica (AIEOP) LNH-97 protocol. Patients aged up to 18 years that were newly diagnosed with BL/DLBCL were included in the study. Therapy consisted of pre-phase followed by 2-6 high-dose chemotherapy courses tailored according to lactate dehydrogenase (LDH) value and disease stage. A total of 442 patients (379 BL, 63 DLBCL) were enrolled between 1997 and 2014, of whom 18 failed to achieve remission, 6 experienced treatment-related death, 2 developed second malignancy and 20 relapsed. At a median follow-up time of 5 years, overall survival was 93% (±1%) and event-free survival was 90% (±1%). LDH value above the median value had an independently negative prognostic value (P < 0·0001). However, in the subgroup of 128 patients in which minimal disseminated disease (MDD) was analysed, MDD-positivity became the only unfavourable prognostic factor for progression-free survival. Tailored chemotherapy could be extremely effective with limited toxicity. Identification of MDD as a hallmark of a higher risk of treatment failure may provide a target population for treatment intensification by anti-CD20.

Early assessment of minimal residual disease identifies patients at very high relapse risk in NPM-ALK-positive anaplastic large-cell lymphoma.

Detection of minimal disseminated disease (MDD) at diagnosis correlates with relapse risk in children with anaplastic lymphoma kinase (ALK)-positive anaplastic large-cell lymphoma (ALCL). We investigated whether minimal residual disease (MRD) positivity by qualitative reverse-transcriptase polymerase chain reaction (RT-PCR) for Nucleophosmin (NPM)-ALK during treatment identifies patients at the highest relapse risk. Blood and/or bone marrow of 180 patients with NPM-ALK-positive ALCL treated with Berlin-Frankfurt-Münster-type protocols were screened for NPM-ALK transcripts at diagnosis; 103 were found to be MDD-positive. MRD before the second therapy course could be evaluated in 52 MDD-positive patients. MRD positivity correlated with uncommon histology. The cumulative incidence of relapses (CIR) of 26 MDD-positive/MRD-positive patients (81% ± 8%) was significantly higher than the CIR of 26 MDD-positive/MRD-negative (31% ± 9%) and 77 MDD-negative patients (15% ± 5%) (P < .001). Five-year survival of MDD-negative and MDD-positive/MRD-negative patients was 91% ± 3% and 92% ± 5%, respectively, compared with 65% ± 9% of MDD-positive/MRD-positive patients (P < .001). Early evaluation of MRD in NPM-ALK-positive ALCL identifies patients with a very high relapse risk and inferior survival.

Impact of persistent minimal residual disease post-consolidation therapy in children and adolescents with advanced Burkitt leukaemia: a Children's Oncology Group Pilot Study Report.

Patient-specific primers from 10 children/adolescents with Burkitt leukaemia (BL) ± central nervous system disease who were treated with French-British-American/Lymphome Malins de Burkitt 96 C1 plus rituximab were developed from diagnostic blood/bone marrow. Minimal residual disease (MRD) was assessed by real-time polymerase chain reaction at the end of induction (EOI) and consolidation (EOC). Seventy per cent (7/10) and 71% (5/7) were MRD-positive at EOI and EOC, respectively, with no disease recurrences. MRD after induction and consolidation did not predict relapse and subsequent therapy appeared to eliminate MRD. Thus, assessing MRD at a later time point is warranted in future trials to determine its clinical significance.